Vehicle seat

ABSTRACT

A vehicle seat including: a tilt down mechanism configured to sink down a seat cushion in conjunction with forward tilting down movement of a seat back; and a link member coupled between the seat back and the seat cushion, wherein the link member is coupled to be slidable relative to either of the seat back and the seat cushion so that, when the seat back is moved within a region in which the seat back is raised from a forward tilted down position, the link member transmits power from the seat back to the seat cushion to pull up the seat cushion, and when the seat back is tilted within an adjustment region of a backrest angle of the seat back, the link member releases the transmission of the power from the seat back to the seat cushion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application No.2014-106665 filed on May 23, 2014, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

Aspects of the present invention relate to a vehicle seat. Moreparticularly, aspects of the present invention relate to a vehicle seatincluding a tilt down mechanism that sinks down a seat cushion inconjunction with forward tilting down movement of a seat back.

BACKGROUND

In related art, a seat for an automobile has been known which has aso-called tilt down mechanism configured to sink down a seat cushion inconjunction with forward tilting down movement of a seat back, therebylowering the entire seat (see JP-A-2009-154682). The tilt down mechanismis configured to suspend a rear part of the seat cushion to the seatback by a link and to obliquely push down the entire seat cushion in afront-lower direction as the seat back is tilted down forward.

According to the above technology, the rear part of the seat cushion issuspended to the seat back by the link. For this reason, since aposition of the seat cushion is changed even when a backrest angle ofthe seat back is tilted rearward, a ride quality is deteriorated. It istherefore an object of the present invention to prevent a seat cushionfrom moving upon adjustment of a backrest angle of a seat back even whena seat is provided with a tilt down mechanism.

SUMMARY

In order to achieve the above object, aspects of the present inventionprovide the following vehicle seat.

According to an aspect of the present invention, there is provided avehicle seat including: a tilt down mechanism configured to sink down aseat cushion in conjunction with forward tilting down movement of a seatback; and a link member coupled between the seat back and the seatcushion and configured to pull up the seat cushion from a sunk-downposition by raising movement of the seat back from a forward tilted downposition, wherein the link member is coupled to be slidable relative toeither of the seat back and the seat cushion so that, when the seat backis moved within a region in which the seat back is raised from theforward tilted down position, the link member transmits power from theseat back to the seat cushion to pull up the seat cushion, and when theseat back is tilted within an adjustment region of a backrest angle ofthe seat back, the link member releases the transmission of the powerfrom the seat back to the seat cushion

Accordingly, when the seat back is raised from the forward tilted downposition, the power is transmitted to the seat cushion through the linkmember, so that the seat cushion is pulled up from the sunk-downposition. However, when the seat back is tilted within the adjustmentregion of the backrest angle, the link member is slid relative to eitherof the seat back and the seat cushion 3, so that the seat cushion iskept at a fixed position without being transmitted with the power. Inthis way, even when the vehicle seat is provided with the tilt downmechanism, it is possible to prevent the seat cushion from moving uponthe adjustment of the backrest angle of the seat back.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating a configuration of a vehicleseat of a first illustrative embodiment;

FIG. 2 is a side view of a seat back;

FIG. 3 is a side view illustrating a state where a backrest angle of theseat back is tilted rearward;

FIG. 4 is a side view illustrating a state where the seat back is tilteddown to a forward tilting position;

FIG. 5 is a side view illustrating a state where the seat back is beingfurther tilted down forward from the forward tilting position;

FIG. 6 is a side view illustrating a state where the seat back is tilteddown forward and a seat cushion is thus sunk down:

FIG. 7 is a side view illustrating a state where the seat back is beingraised from the position at which the seat back is tilted forward: and

FIG. 8 is an enlarged view of a VIII part of FIG. 2.

DETAILED DESCRIPTION

Hereinafter, an illustrative embodiment of the present invention will bedescribed with reference to the drawings.

First Illustrative Embodiment

First, a configuration of a seat I of a first illustrative embodiment isdescribed with reference to FIGS. 1 to 8. As shown in FIG. 1, the seat 1of the illustrative embodiment is configured as a rear seat for anautomobile, and a luggage space LS of a vehicle is formed at the rear ofthe seat 1. The seat 1 has a seat back 2 serving as a backrest of asitting passenger and a seat cushion 3 serving as a sitting part. Theseat 1 has a reclining mechanism REC configured to adjust a backrestangle of the seat back 2, and a tilt down mechanism TD (see FIGS. 4 to6) configured to sink down the seat cushion 3 in conjunction withforward tilting down movement of a seat back.

The reclining mechanism REC is configured to fix the backrest angle ofthe seat back 2 with respect to a vehicle side part and to change thebackrest angle of the seat back 2 by changing the fixed position withrespect to the vehicle side part. As shown in FIGS. 4 to 6, the tiltdown mechanism TD is configured to drop the seat cushion 3 onto a floorF in conjunction with the forward tilting down movement of the seat back2, thereby tilting down the seat back 2 to a low position flush with aluggage floor LF, as shown in FIG. 6.

In the illustrative embodiment, although the seat 1 is configured todrop the seat cushion 3 in conjunction with the forward tilting downmovement of the seat back 2 by the tilt down mechanism TD, the seat 1 isalso configured to prevent the seat cushion 3 from moving when the seatback 2 is tilted within an adjustment region of the backrest angle. Bythe configuration, even when the backrest angle of the seat back 2 ischanged, it is possible to keep the seat cushion 3 at a fixed positionall the time, thereby maintaining a favorable ride quality. In thebelow, the specific configurations of the respective parts of the seat 1are described in detail.

As shown in FIG. 1, the seat back 2 is coupled at lower end portions ofboth left and right sides thereof to a pair of left and right rear basesFB fixed on the floor F by coupling shafts 2A so that it can be rotatedrearward and forward. Specifically, the seat back 2 has a configurationwhere respective brackets 2B coupled to lower end portions of both leftand right sides of a back frame 2F forming a frame of the seat back 2are rotatably coupled to each of a pair of left and right rear bases FBfixed on the floor F by the respective coupling shafts 2A of which anaxis direction faces towards a width direction of the seat.

Although not shown, the seat back 2 has a configuration where a lockdevice provided at a shoulder part of a vehicle outer side, which is aleft side of FIG. 1, is locked to a striker provided at the vehicle sidepart, so that the backrest angle is fixed. The striker, which is notshown, is attached to the vehicle side part to be slidable rearward andforward and can be locked at each slid position. Thereby, the backrestangle of the seat back 2 fixed by the striker can be adjusted bychanging a slide position of the striker (the reclining mechanism REC).

As shown in FIGS. 2 and 3, a moveable range of the striker (not shown)is set within an angle range in which the seat back 2 is tilted rearwardfrom an upright posture. Thereby, it is possible to fix the backrestangle of the seat back 2 within the moveable range of the striker sothat the backrest angle can be adjusted relative to the vehicle sidepart. In the meantime, since the specific configuration of the recliningmechanism REC (see FIG. 1) is the same as the well-known configurationdisclosed in Japanese Patent No. 5,382,709, for example, the specificdescription thereof is omitted. When the locked state of the seat back 2to the striker is released, the seat back 2 can be tilted forward beyondthe adjustable range of the backrest angle, as shown in FIGS. 4 to 6.

As shown in FIG. 1, the seat cushion 3 is coupled at rear end portionsof both left and right sides thereof to the pair of left and right rearbases FB fixed on the floor F by one rotary shaft 3A, which is long inthe width direction of the seat, so that it can be rotated in a heightdirection. Specifically, the seat cushion 3 has a configuration whererear end portions of both left and right sides of a cushion frame 3F,which is formed by bending a round pipe forming a frame of the seatcushion 3 into a U shape, are rotatably coupled to each of the pair ofleft and right rear bases FB fixed on the floor F by the one rotaryshaft 3A of which an axis direction faces towards the with direction ofthe seat. Here, each rear base FB corresponds to the ‘base’ of thepresent invention.

The seat cushion 3 has a configuration where front parts of both leftand right sides thereof are respectively coupled to each of a pair ofleft and right front bases FA fixed on the floor F via front links 4 ata raised position. Specifically, the seat cushion 3 has a configurationwhere upper end portions of the respective front links 4 arerespectively coupled to a pair of left and right guide plates 3G, whichare coupled to a front frame part of the cushion frame 3F and extendrearward, to be rotatable and to be slidable rearward and forward viaslide shafts 4A. Each slide shaft 4A is coupled in a long hole 3G1,which is formed at the guide plate 3G and extends rearward and forward,to be rotatable and to be slidable rearward and forward with an axisdirection thereof facing towards the width direction of the seat.

A lower end portion of each front link 4 is rotatably coupled to eachfront base FA by each coupling shaft 4B of which an axis direction facestowards the width direction of the seat. Thereby, each front link 4 canbe rotated to rise or fall rearward and forward about the lower end-sidecoupling shaft 4B within the range in which the upper end-side slideshaft 4A can slide rearward and forward in the long hole 3G1 of theguide plate 3G.

As shown in FIG. 2, when each front link 4 is rotated to rise forwardabout the lower end-side coupling shaft 4B, the upper end-side slideshaft 4A is slid to a front end portion position in the long hole 3G1 ofthe guide plate 3G, so that the front link 4 takes a posture standing upto a substantially vertical angle position from each front base FA.Thereby, a front side part of the seat cushion 3 is supported at anangle posture of a front rising shape.

At this state (state where each slide shaft 4A is slid to the front endportion position in the long hole 3G1 of each guide plate 3G), eachfront link 4 takes a posture where a line 4L connecting the upperend-side slide shaft 4A and the lower end-side coupling shaft 4B forms atangential line of a circle Ci drawn around the rear end-side rotaryshaft 3A of the seat cushion 3. Thereby, each front link 4 supports theseat cushion 3 from below at a stable posture where the front link isnot tilted even when the load is applied thereto from the seat cushion3.

Also, a retraction belt 5 is coupled between each front link 4 and theseat back 2. When the seat back 2 is tilted forward, the retraction belt5 pulls each front link 4 so that each front link 4 is tilted rearward.The retraction belt 5 is configured by a flexible band-shaped member andis coupled between a bridging shaft 4C bridged between the respectivefront links 4 and the back frame 2F forming a frame of the seat back 2.

Specifically, the retraction belt 5 is configured to pass through alower region of the seat cushion 3 at the center in the width directionof the seat, to extend rearward from a coupled part with the bridgingshaft 4C, and to be contacted and supported at a substantially centralpart of the seat cushion 3 in the front-rear direction from a lower sideof the retraction belt by a first belt guide 3D1 so that it is bent intoa mountain shape. Also, the retraction belt 5 is configured to becontacted and supported at a rear end part of the seat cushion 3 from anupper side thereof by a second belt guide 3D2 so that it is bentupwardly. The retraction belt 5 is attached to a belt attaching part 2D3attached to a lower frame part of the back frame 2F.

As shown in FIG. 1, the first belt guide 3D1 is attached between a pairof left and right support wires 3W bridged between the front and rearbridging frames 3B bridged between both side frame parts of the cushionframe 3F forming a frame of the seat cushion 3. In the meantime, each ofthe pair of left and right guide plates 3G coupled to the front framepart of the cushion frame 3F is also integrally coupled at its upperedge portion to the front bridging frame 3B, and is thus stronglysupported.

The second belt guide 3D2 is attached to a central part of the longrotary shaft 3A in the width direction of the seat, which is configuredto shaft-support the rear end portion of the seat cushion 3 to each rearbase FB. The second belt guide 3D2 has a wheel shape and is formed tobend and guide the retraction belt 5 upwardly from the lower region ofthe rotary shaft 3A via the rear region. The belt attaching part 2D3 hasalso a wheel shape and is configured to attach an end portion of theretraction belt 5 to a lower position of the lower frame part of theback frame 2F at a state where the seat back 2 is located within theadjustment region of the backrest angle, as shown in FIGS. 2 and 3.

As specifically shown in FIGS. 2 and 3, the retraction belt 5 is slackat a state where the seat back 2 is located within the adjustment regionof the backrest angle, and does not transmit a tensile force, which isaccompanied by a change in the backrest angle of the seat back 2, toeach front link 4 even when the backrest angle of the seat back 2 ischanged in the adjustment region. As shown in FIG. 4, when the seat back2 is tilted down forward to a position, which is set as a hip point HPof a sitting passenger, the retraction belt 5 is wound onto the beltattaching part 2D3 and is retracted into the seat back 2, so that theretraction belt 5 is at a tensioned state with the slackness thereofbeing removed.

As shown in FIGS. 5 and 6, when the seat back 2 is further tilted downforwards from the forward tilting position shown in FIG. 4, theretraction belt 5 is further wound onto the belt attaching part 2D3, sothat it transmits the forward tilting down movement of the seat back 2to the respective front links 4 and thus tilts down rearward therespective front links 4. Thereby, the seat cushion 3 is pushed downabout the rear end-side rotary shaft 3A to drop the front part thereofonto the floor F, so that the seat back 2 is tilted down into an emptyspace and the whole seat 1 is deeply sunk down.

Also, as shown in FIG. 1, two tensile springs 4S are hooked between therespective front links 4 and the respective front bases FA. The tensilesprings 4S are respectively hooked at left and right sides between abridging shaft 4D bridged between the respective front links 4 and ahanging wire FA1 bridged between the respective front bases FA. As shownin FIGS. 2 and 3, when each front link 4 is located within an uprightrotating angle region, the tensile spring 4S passes over a region upperto the lower end-side coupling shaft 4B of each front link 4, therebyapplying a rotational urging force to each front link 4 in a forwardraising direction.

However, as shown in FIGS. 5 and 6, when each front link 4 is tiltedrearward as the seat back 2 is tilted forward, each tensile spring 4Straverses a region lower to the lower end-side coupling shaft 4B of eachfront link 4. Thereby, the direction of the rotating urging forceapplied to each front link 4 is switched, so that each tensile spring 4Sapplies the rotating urging force to each front link 4 in a rearwardtilting direction.

The turnover-type tensile springs 4S are hooked between the respectivefront links 4 and the respective front bases FA, so that when therespective front links 4 are located at the upright rotating posture, asshown in FIGS. 2 and 3, the respective slide shafts 4A thereof are keptin a state of being pressed to the front end portion positions of thelong holes 3G1 of the respective guide plates 3G. Thereby, as describedabove, each front link 4 is configured to stably keep the uprightposture state where the front link 4 is not tilted even when the load isapplied thereto from the seat cushion 3.

Also, as shown in FIGS. 5 and 6, when the respective front links 4 areretracted and tilted rearward by the retraction belt 5 as the seat back2 is tilted forward, the respective front links 4 are pressed and keptin a state of being tilted rearward by the urging force of therespective tensile springs 4S. Thereby, each front link 4 is stably keptin a state of being pressed to the floor F without rattling on the floorF.

As shown in FIG. 1, a tensile link 6, which is configured to pull up theseat cushion 3 from the sunk-down position on the floor F as the seatback 2 is raised rearward from the forward tilted position shown in FIG.6, is respectively coupled between both side parts of the seat back 2and the seat cushion 3. As shown in FIG. 1 each of the tensile links 6is configured by a plate member that is bent into a crank shape in thewidth direction of the seat and is long in the height direction. Here,each tensile link 6 corresponds to the ‘link member’ of the presentinvention.

An upper end portion of the tensile link 6 is rotatably coupled to eachbracket 2B, which is coupled to each lower end portion of both left andright sides of the back frame 2F forming a frame of the seat back 2, bya coupling shaft 6A of which an axis direction faces towards the widthdirection of the seat. As shown in FIGS. 2 and 3, each of the couplingshafts 6A is arranged so that it is positioned in a region at anupper-rear side of each rotary shaft 2A serving as a center of rotationof the seat back 2 at a state where the seat back 2 is located withinthe adjustment region of the backrest angle.

Also, a lower end portion of each tensile link 6 is coupled to each longhole 3F1, which is formed at each of both left and right side frameparts of the cushion frame 3F forming a frame of the seat cushion 3, viaa slide shaft 6B so that it can be rotated and slid rearward andforward. Each long hole 3F1 formed at each side frame part of thecushion frame 3F is formed as a penetrated hole straightly extending inthe front-rear direction along which each side frame part extends.

As shown in FIGS. 2 and 3, when the seat back 2 is located within theadjustment region of the backrest angle, each tensile link 6 is providedto follow a side shape of the seat back 2 or seat cushion 3 at a statewhere the lower end-side slide shaft 6B is positioned in a rear sideregion of the long hole 3F1. Thereby, each tensile link 6 is provided ata position at which it does not interfere with a sitting passenger,without protruding forward from the seat back 2 or protruding upwardlyfrom the seat cushion 3.

As shown in FIGS. 4 to 6, each tensile link 6 is configured to slideforward in the long hole 3F1 so that the lower end-side slide shaft 6Bis pushed from the rear by the upper end-side coupling shaft 6A as theseat back 2 is tilted down forward. As shown in FIG. 6, when the seatback 2 is completely tilted down forward, the upper end-side couplingshaft 6A of the tensile link 6 is positioned in a front region of eachrotary shaft 2A, which is a center of rotation of the seat back 2, andthe lower end-side slide shaft 6B is positioned in the front end-sideregion of the long hole 3F1.

As shown in FIG. 7, each tensile link 6 is operated so that the lowerend-side slide shaft 6B is pulled up in the rear-upper direction by theupper end-side coupling shaft 6A as the seat back 2 is raised rearwardfrom the tiled down state onto the floor F (see FIG. 6). Thereby, eachtensile link 6 pulls up the seat cushion 3 coupled to the lower end-sideslide shaft 6B thereof around the rear end-side rotary shaft 3A, therebyreturning the seat cushion 3 to an initial sitting using position beforethe seat cushion 3 is sunk down onto the floor F. Specifically, eachtensile link 6 is configured to pull up the seat cushion 3 as the lowerend-side slide shaft 6B is slid rearward in each long hole 3F1.

At this time, at the state where the seat back 2 is tilted down onto thefloor F (see FIG. 6), each tensile link 6 can raise the seat cushion 3around the rear end-side rotary shaft 3A with a relatively weak force bythe force with which the seat back 2 is raised rearward, because thelower end-side slide shaft 6B is positioned in the front end-side regionof the long hole 3F1. The reason is that each slide shaft 6B is arrangedat a position (front end-side region of each long hole 3F1) spacedforward from the rear end-side rotary shaft 3A of the seat cushion 3.

Also, at the state where the seat back 2 is tilted down onto the floor F(see FIG. 6), each tensile link 6 can effectively pull up the seatcushion 3 by the operating movement amount with which the seat back 2 israised rearward, because the upper end-side coupling shaft 6A ispositioned in the front region of each rotary shaft 2A, which is acenter of rotation of the seat back 2. The reason is that as eachcoupling shaft 6A is raised towards the rear of the seat back 2, eachcoupling shaft 6A passes through the region largely moving upwardsaround each rotary shaft 2A, which is a center of rotation of the seatback 2.

As the seat back 2 is raised and the seat cushion 3 is thus pulled up,the upper end-side slide shaft 4A is guided by the shape of each longhole 3G1 formed at the guide plate 3G of the seat cushion 3, so thateach front link 4 is also slid and raised forward. When the seat back 2is returned to the backrest using position (adjustment region of thebackrest angle) as shown in FIG. 2, the upper end-side slide shaft 4A isapplied with the urging force of each tensile spring 4S and is returnedto the state where it is pressed to the front end portion position ofeach long hole 3G1 of the seat cushion 3, so that each front link 4stably supports the seat cushion 3 from below at the initial sittingusing position.

By the above movement, the lower end-side slide shaft 6B of each tensilelink 6 is slid rearward to the rear side region in the long hole 3F1.However, each long hole 3F1 is formed to have a rearward extensionmargin A within which each slide shaft 6B can be further slid rearward,as shown in FIG. 8, so that the slide shaft 6B does not reach the rearend portion position of each long hole 3F1. By this configuration, asshown in FIGS. 2 and 3, even when the seat back 2 is angle-changedrearward and forward within the adjustment region of the backrest angle,each slide shaft 6B is slid within the extension margin A of each longhole 3F1, so that the movement can be released. Therefore, when thebackrest angle of the seat back 2 is adjusted, each tensile link 6 cankeep the seat cushion 3 at the fixed position all the time withoutfurther raising or dropping the seat cushion 3.

Specifically, in the adjustment region of the backrest angle of the seatback 2, each tensile link 6 is configured so that the upper end-sidecoupling shaft 6A passes through the region largely moving rearward andforward around each rotary shaft 2A, which is a center of rotation ofthe seat back 2, by the tilting movement of the seat back 2. Thereby,each tensile link 6 is moved so that the lower end-side slide shaft 6Bis slid rearward and forward in the extension margin A of each long hole3F1 of the seat cushion 3, in response to the above movement. For thisreason, each tensile link 6 is not largely moved in the heightdirection, and can absorb the movement, which makes each coupling shaft6A move rearward and forward around the rotary shaft 2A serving as acenter of rotation of the seat back 2, by the movement of the slidercrank that each slide shaft 6B slides rearward and forward in the longhole 3F1, while keeping the seat cushion 3 at the fixed position.

In summary, the seat 1 of the illustrative embodiment is configured asfollows. That is, the seat 1 includes the tilt down mechanism TDconfigured to sink down the seat cushion 3 in conjunction with theforward tilting movement of the seat back 2. The seat 1 includes thelink member (tensile link 6) coupled between the seat back 2 and theseat cushion 3 and configured to pull up the seat cushion 3 from thesunk-down position by the raising movement of the seat back 2 from theforward tilted down position. The link member (tensile link 6) iscoupled to be slidable relative to either of the seat back 2 and theseat cushion 3 (the seat cushion 3) so that, when the seat back 2 ismoved within the region in which the seat back 2 is raised from theforward tilted down position, the link member transmits the power fromthe seat back 2 to the seat cushion 3 to pull up the seat cushion 3, andwhen the seat back 2 is tilted within the adjustment region of thebackrest angle of the seat back 2, the link member releases thetransmission of the power from the seat back 2 to the seat cushion 3.

By the above configuration, when the seat back 2 is raised from theforward tilted down position, the power is transmitted to the seatcushion 3 through the link member (the tensile link 6), so that the seatcushion 3 is pulled up from the sunk-down position. However, when theseat back 2 is tilted within the adjustment region of the backrestangle, the link member (tensile link 6) is slid relative to either ofthe seat back 2 and the seat cushion 3 (the seat cushion 3), so that theseat cushion is kept at the fixed position without being transmittedwith the power. In this way, even when the seat 1 is provided with thetilt down mechanism TD, it is possible to prevent the seat cushion 3from moving upon the adjustment of the backrest angle of the seat back2.

Also, the tilt down mechanism TD couples the rear part of the seatcushion 3 to the base (rear base FB) on the floor F by the rotary shaft3A and is configured to sink down the front part of the seat cushion 3about the rotary shaft 3A at the rear side. The link member (tensilelink 6) is configured to be slid forward relative to the seat cushion 3in conjunction with the forward tilting movement of the seat back 2 andto be slid rearward relative to the seat cushion 3 to pull up the seatcushion 3 in conjunction with the raising movement of the seat back 2.Further, the link member (tensile link 6) is also configured to be slidrelative to the seat cushion 3 in the adjustment region of the backrestangle of the seat back 2, thereby releasing the power transmission fromthe seat back 2 to the seat cushion 3.

By the above configuration, when pulling up the seat cushion 3, the linkmember (tensile link 6) pulls up the seat cushion 3 at the positionspaced forward from the rear side rotary shaft 3A. For this reason, itis possible to smoothly pull up the seat cushion 3 by the link member(tensile link 6). In this configuration, the seat cushion 3 side (notthe seat back 2 side) is set as an object to which the link member(tensile link 6) is slidably coupled so as to release the powertransmission within the adjustment region of the backrest angle of theseat back 2. Thereby, the link member (tensile link 6) is coupled sothat the link member can be slid rearward and forward relative to theseat cushion 3 within a sequential range (each slide shaft 6B is coupledin each long hole 3F1). Therefore, it is possible to integrate andstreamline the two slidably coupled structures.

Also, the seat cushion 3 is configured to sink down to the floor F sothat the front part thereof is dropped about the rear side rotary shaft3A by the tilt down mechanism TD. In general, as shown in FIG. 2, theseat cushion 3 is configured in many cases so that a pad thickness of acushion pad 3P in the height direction is set to be thick in the rearregion of the seat cushion 3 so as to support hip parts having a highsitting pressure and is set to be relatively thinner in the front regionof the seat cushion 3 to support the femoral regions, as compared to thepad thickness in the rear region of the seat cushion 3, and the seatcushion 3 is formed to have the front rising shape so as to prevent thehip parts from sliding forward. Therefore, when the seat cushion 3 isconfigured to sink down to the floor F so that the front part thereof isdropped about the rear side rotary shaft 3A, as described above, it ispossible to effectively sink down the seat cushion 3 also in a narrowsinking space.

Although the illustrative embodiment of the present invention has beendescribed with reference to one example, the present invention can beimplemented in a variety of aspects, in addition to the aboveillustrative embodiment. For example, the ‘vehicle seat’ of the presentinvention can be applied to a seat of an automobile other than the rearseat, and can also be applied to a variety of vehicle seats such as a‘seat for a train’, a ‘seat for an airplane’ and a ‘seat for a ship’.The base on the floor configured to couple the rear part of the seatcushion by the rotary shaft may be configured by a member fixed on thefloor such as a slide rail.

Also, the link member may be coupled to be slidable relative to the seatback so that, when the seat back is moved within a region in which theseat back is raised from the forward tilted down position, the linkmember transmits power from the seat back to the seat cushion to pull upthe seat cushion, and when the seat back is tilted within the adjustmentregion of the backrest angle of the seat back, the link member releasesthe transmission of the power from the seat back to the seat cushion.

Also, the configuration of the present invention is not limited to acase where it is applied to the narrow sinking space of the seatcushion, and can also be applied to a wide sinking space. That is, thepresent invention can be applied to a variety of configurations, as oneof methods of sinking down the seat cushion.

The present invention provides illustrative, non-limiting aspects asfollows:

According to an aspect of the present invention, there is provided avehicle seat including: a tilt down mechanism configured to sink down aseat cushion in conjunction with forward tilting down movement of a seatback; and a link member coupled between the seat back and the seatcushion and configured to pull up the seat cushion from a sunk-downposition by raising movement of the seat back from a forward tilted downposition, wherein the link member is coupled to be slidable relative toeither of the seat back and the seat cushion so that, when the seat backis moved within a region in which the seat back is raised from theforward tilted down position, the link member transmits power from theseat back to the seat cushion to pull up the seat cushion, and when theseat back is tilted within an adjustment region of a backrest angle ofthe seat back, the link member releases the transmission of the powerfrom the seat back to the seat cushion

Accordingly, when the seat back is raised from the forward tilted downposition, the power is transmitted to the seat cushion through the linkmember, so that the seat cushion is pulled up from the sunk-downposition. However, when the seat back is tilted within the adjustmentregion of the backrest angle, the link member is slid relative to eitherof the seat back and the seat cushion 3, so that the seat cushion iskept at a fixed position without being transmitted with the power. Inthis way, even when the vehicle seat is provided with the tilt downmechanism, it is possible to prevent the seat cushion from moving uponthe adjustment of the backrest angle of the seat back.

In the above vehicle seat, the tilt down mechanism may couple a rearpart of the seat cushion to a base on a floor by a rotary shaft and maybe configured to sink down a front part of the seat cushion about therotary shaft. The link member may be configured to be slid forwardrelative to the seat cushion in conjunction with the forward tiltingdown movement of the seat back and to be slid rearward relative to theseat cushion to pull up the seat cushion in conjunction with the raisingmovement of the seat back. The link member may be also configured to beslid relative to the seat cushion in the adjustment region of thebackrest angle of the seat back, thereby releasing the transmission ofthe power from the seat back to the seat cushion.

Accordingly, when pulling up the seat cushion, the link member pulls upthe seat cushion at a position spaced forward from the rear side rotaryshaft. For this reason, it is possible to smoothly pull up the seatcushion by the link member. In this configuration, the seat cushion sideis set as an object to which the link member is slidably coupled so asto release the power transmission within the adjustment region of thebackrest angle of the seat back. Thereby, the link member is coupled sothat the link member can be slid rearward and forward relative to theseat cushion within a sequential range. Therefore, it is possible tointegrate and streamline the two slidably coupled structures.

What is claimed is:
 1. A vehicle seat comprising: a tilt down mechanismconfigured to sink down a seat cushion in conjunction with forwardtilting down movement of a seat back; and a link member coupled betweenthe seat back and the seat cushion and configured to pull up the seatcushion from a sunk-down position by raising movement of the seat backfrom a forward tilted down position, wherein the link member is coupledto be slidable relative to either of the seat back and the seat cushionso that, when the seat back is moved within a region in which the seatback is raised from the forward tilted down position, the link membertransmits power from the seat back to the seat cushion to pull up theseat cushion, and when the seat back is tilted within an adjustmentregion of a backrest angle of the seat back, the link member releasesthe transmission of the power from the seat back to the seat cushion. 2.The vehicle seat according to claim I, wherein the tilt down mechanismcouples a rear part of the seat cushion to a base on a floor by a rotaryshaft and is configured to sink down a front part of the seat cushionabout the rotary shaft, wherein the link member is configured to be slidforward relative to the seat cushion in conjunction with the forwardtilting down movement of the seat back and to be slid rearward relativeto the seat cushion to pull up the seat cushion in conjunction with theraising movement of the seat back, and wherein the link member is alsoconfigured to be slid relative to the seat cushion in the adjustmentregion of the backrest angle of the seat back, thereby releasing thetransmission of the power from the seat back to the seat cushion.